2, 4-dimethyl-2, 4-trimethylsilylphenyl-2, 4-disilapentane



Patented May 16, 1950 2,4-DIMETHYL-2,4-TRIMETHYLSILYL PHENYL-ZA-DISILAPENTANE Harold A. Clark, Midland, Mich., assignor to Dow Corning Corporation, Midland, Mich., a corporation of Michigan No Drawing. Application February 23, 1949', Serial No. 77,989

2 Claims.

This invention relates to an organo silicon polymer.

It is an object of this invention to prepare a thermally stable compound which is of particular utility as a lubricant and a vacuum diffusion pump fluid. Other objects and advantages will be apparent from the following description.

This invention relates to the compound CH3 CH3 (OHahSlCaHAiCHaiGeHlSi(CH3):

Ha H! The compound of this invention may be prepared by a condensation reaction between chlorophenyltrimethylsilane and in the presence of sodium. Th latter compound may be obtained by reacting a methyl Grignard reagent with the compound ClsSiCHzSiCla and purification by distillation. The condensation reaction proceeds according to the equation The compound of this invention is a clear oil having a viscosity of 28.3 cs. at 25 0., a boilin point of 171 at 1 mm., a freezing point of 54 C., a refractive index of 1.5113 at 25 C. and a density of 0.923 at 25 C. This material is stable when heated at a temperature of 365 C. in the absence of oxygen and is stable at temperatures up to 200 C. in the presence of oxygen. The compound performs satisfactorily when used to lubricate the bearing surfaces of moving metallic parts. It is also a good vacuum diffusion pump fluid as is shown by the following tests.

A sample of the compound was placed in a single stage diffusion pump and operated at 135 C. with a fore pressur of 30 microns. A vacuum of 8.1 mm. was obtained. During the operation of the pump the material showed no sign of deterioration.

In order that this invention may be better understood, recourse should be had to the following example, which should be considered as illustrative only.

Example 184.5 g. of chlorophenyltrimethylsilane was mixed with 100.5 of Ol(CH3)2SiCH2Si(CH3) 2G1 and the mixture was added to g. of molten sodium in 800 cc. of refluxing toluene. The reaction was exothermic so that the solvent :could be maintained at reflux by regulating the rat of addition of the chlorosilanes. After addition of the silanes was completed the mixture was refiuxed for an additional hour. The material was then filtered and the toluene was removed at reduced pressure. The residue was a clear oil which distilled at 171 C. at 1 mm. pressure. The compound was found to have a molar refraction of 141.77.

That which is claimed is:

OH; OH: (OHOlSlCoHaAiCHiAiOeHASKOHJ)! Ha H:

2. A method of preparing CH; CH; CH: (C 1)liCgHl iCfiggiCaHlsiw H1);

H H: H:

which comprises reacting chlorophenyltrimethylsilane and C1(CHa)2SiCH2Si(CH3)2C1 by contacting a mixture thereof with metallic sodium.

HAROLD A. CLARK.

REFERENCES CITED The following references are of record in the file of this patent:

Goodwin: Jour. Am. Chem. 800., vol. 69 (1947), page 2247.

Sommer: Jour. Am. Chem. 800., vol. 69 (1947), page 980.

Bluestein: Jour. Am. Chem. Soc, vol. 70 (1948), pages 3068-3071. 

